This invention is an stent and stent delivery system which may be used within various portions of the body's vasculature. In general, stents are prosthetic devices which may be introduced into a body cavity such as the lumen of a blood vessel or in some other difficult to access location. Stents are particularly useful for permanently widening a vessel which is either in a narrowed condition or has been damaged by aneurysm. Stents are typically introduced into the vasculature or other body cavity by the use of a catheter. Stents are usually tubular bodies made up of radially stiff shapes (for example circles) connected together to form the tubular shape.
Currently, the majority of stents are delivered to the target site as radially expandable preformed structures. In other words, only the diameter of the stent may be increased or decreased once properly positioned in the region where they are to be left. For instance, WO 92/02,246, owned by Numed, Inc., shows a radially expandable stent made from fine wire formed into a serpentine ribbon wound into a cylindrical shape for introduction into a body vessel. The stent is placed within the vessel over a balloon which, when expanded, expands the stent in a radial fashion to support the wall of the vessel in the expanded configuration. This stent is said to be useful in the transluminar implantation of a stent for use in coronary angioplasty to prevent restenosis.
Other disclosures of expandable intraluminal stents involving radially expanding wire mesh include U.S. Pat. No. 4,776,337, to Palmaz. The patent shows a tubular member which may be made of a variety of different things supported by a gridlike collection of metal or plastic wires. U.S. Pat. No. 4,800,882, to Gianturco, shows a wire stent made of a number of curved sections that are formed into a generally circular configuration. U.S. Pat. No. 6,007,573 shows a rolled sheet stent releasably mounted on the distal tip of the deployment catheter. U.S. Pat. No. 06,063,101 shows a balloon expandable stent which includes a hollow wire through which drugs and the like are delivered to the stent itself. The hollow wire is detached after drug deliver using ultrasonic energy.
Stents delivered to a restricted coronary artery, expanded to a larger diameter as by a balloon catheter, and left in place in the artery at the site of a dilated lesion are shown in U.S. Pat. No. 4,740,207 to Kreamer; U.S. Pat. No. 5,007,926 to Derbyshire; U.S. Pat. No. 4,733,665 to Palmaz; U.S. Pat. No. 5,026,377 to Burton et al.; U.S. Pat. No. 5,158,548 to Lau et al.; U.S. Pat. No. 5,242,399 to Lau et al.; U.S. Pat. No. 5,344,426 to Lau et al.; U.S. Pat. No. 5,415,664 to Pinchuk; U.S. Pat. No. 5,453,090 to Martinez et al.; U.S. Pat. No. 4,950,227 to Savin; U.S. Pat. No. 5,403,341 to Solar; U.S. Pat. No. 5,108,416 to Ryan et al. and European Patent Application No. 707 837 A1 to Sheiban, all of which are incorporated herein by reference.
WO 97/48351, to the Medical University of South Carolina, discloses a multiple layered, self-forming intravascular flow modifier (IFM). Notably, at least a portion of the outer layer surrounds at least a portion of the inner layer so that at least some loops of the outer layer overlap and contact at least some loops of the inner layer. In other words, the turns making up the final configuration are necessarily overlapping and touching each other. The IFM also has a relatively high stiffness. The IFM is deployed using co-axial catheters.
None of these documents depict self-expandable or self-forming stents having a wire attached to the proximal end of the stent and/or the distal end of the stent which allow the operator to position the stent in situ. Further, none describe a self-forming stent which forms a tubular structure of turns from a substantially linear configuration upon deployment and in which the turns making up the tubular structure do not contact each other. Thus, the present invention is particularly directed to stents which can be configured upon deployment and delivery systems which facilitate delivery thereof.